MASTRA

Sam is one of the most credentialled developer tools founders in the JavaScript ecosystem, and the lineage from Gatsby to Mastra is not a pivot, it is a continuous extension of the same core conviction: that framework design is a craft, and that getting it right creates outsized leverage for the developers who use it. He studied Economics at Stanford (BA, class of 2011) after beginning his studies in 2005, including a two-year break for missionary work, an unusual biographical detail that speaks to the same person who later describes framework design in almost philosophical terms. After Stanford he worked as an associate consultant at Mars & Company briefly, then as CFO at Blueseed (the startup seasteading project), before pivoting fully into engineering at Boingo Wireless, then early-stage engineering roles at Zenefits (YC W13) and PlanGrid (YC W12), both high-growth San Francisco enterprise companies where he was among the first 20 engineers. He co-founded Gatsby in 2018 and served as co-founder until 2023, scaling it from an open-source React site generator to a product used by hundreds of thousands of developers, raising $50M in venture funding and growing to $5M ARR before acquisition by Netlify. He then served briefly as Principal Engineer at Netlify post-acquisition before leaving to start Mastra in July 2024, within months of leaving, the company was in YC and raising $13M. He authored 'Principles of Building AI Agents' in 2025, which he describes as 'the most popular book in SF right now,' and which has become a community artefact in the Mastra ecosystem. His public writing on X (@calcsam) and the Mastra blog consistently returns to the craft of API design: the naming choices, the progressive disclosure decisions, the interoperability principles that determine whether a framework becomes the default or the also-ran.

Abhi is the infrastructure half of Mastra's founding trio and the person most directly responsible for the reliability properties that make Mastra viable as enterprise infrastructure rather than just a developer toy. His role at Netlify as Principal Engineer and lead of a 100+ person engineering organisation is the credential that matters most: he built the Gatsby Cloud infrastructure, tens of thousands of build nodes, billions of files served, hundreds of terabytes of monthly bandwidth, which means he understands at first-hand what it takes to go from an open-source framework with great developer experience to a cloud platform that enterprise teams can actually depend on. That transition is exactly what Mastra is executing now with the Series A platform launch. His role as CTO at Mastra means he is making the architectural decisions about Mastra Server, the Memory Gateway, and the enterprise tier features that determine whether the platform can support the Bx and Workday-scale deployments already in production.

Shane is the product and community half of the founding team, and his background is the piece that explains why Mastra's developer experience feels as deliberate as it does. He served as Staff Engineer and Head of Product at Gatsby, giving him both engineering depth and product ownership experience across the same framework's growth arc that Sam led commercially. He previously built Audiofeed, an AI podcasting product, which means he has direct experience as a solo product builder shipping AI-native consumer products before Mastra existed as a concept. The YC profile adds one biographical detail that is worth noting in the context of recruiting: 'state wrestling champion.' That is the background of someone with a competitive drive and discipline orientation that shows up in how he talks about open-source, his public writing on 15+ years in open source is oriented around craft and community, not individual recognition.